The books are based around a mouse named Ricky Ricotta and his mighty robot. Once an Episode, the duo defeats a Monster of the Week from a different planet in the Solar System coinciding with its Alliterative Name. (In fact, the planets are in order from closest-to-furthest from the Sun excluding Earth, which is where the first book's villain is from.) Each book ends with the villain being thrown into jail alongside the other villains in the series. The books also incorporate the "Flip-O-Rama" mechanism from Captain Underpants for quote-unquote "action scenes".
The series was formerly called Ricky Ricotta's Giant Robot, which Pilkey used when he published the first three books. Young readers were quick to point out that the robot was only giant in relation to Ricky Ricotta's size (if he is 12 times taller than a mouse, he's only about 2.5 feet tall) and suggested that the adjective be eschewed for "mighty", which Pilkey did.
After the Book o' Fun (also taken from Captain Underpants) was released, the series went into a seven-year hiatus. In October 2013, it was announced
that the series was due for a rebooting with a new artist, Promoted Fanboy Dan Santat, who not only re-illustrated the whole series but also illustrated two long-awaited remaining books not published during the Ontiveros era.
Books:
- Ricky Ricotta's Mighty Robot (2000)
- Ricky Ricotta's Mighty Robot vs. the Mutant Mosquitoes from Mercury (2000)
- Ricky Ricotta's Mighty Robot vs. the Voodoo Vultures from Venus (2001)note
- Ricky Ricotta's Mighty Robot vs. the Mecha Monkeys from Mars (2002)
- Ricky Ricotta's Mighty Robot vs. the Jurassic Jackrabbits from Jupiter (2002)
- Ricky Ricotta's Mighty Robot vs. the Stupid Stinkbugs from Saturn (2003)
- Ricky Ricotta's Mighty Robot vs. the Uranium Unicorns from Uranus (2005)
- Ricky Ricotta's Mighty Robot Astro-Activity Book o' Fun (2006)
- Ricky Ricotta's Mighty Robot vs. the Naughty Night Crawlers from Neptune (2015)
- Ricky Ricotta's Mighty Robot vs. the Un-Pleasant Penguins from Pluto (2016)
These books contain examples of:
- Added Alliterative Appeal: Every book title besides the first one, after the "vs." part.
- A.I. Is a Crapshoot: Inverted with the Robot. It was built and programmed to destroy the city but it refused to do so, and turns good instead, protecting the city thereafter.
- Alliterative Name: Ricky Ricotta himself.
- Also, the villains starting with Mr. Mosquito - after him comes Victor von Vulture, Major Monkey, General Jackrabbitnote , Sergeant Stinkbug, Uncle Unicorn, Nimrod Nightcrawler, and President Penguin.
- Annoying Younger Cousin: Lucy, who, as Ricky puts it, is "a little pest!"
- Armies Are Evil: Major Monkey and General Jackrabbit are both portrayed as Jerkass military leaders who want to Take Over the World. Sergeant Stinkbug goes a step further, wishing to turn Earth into his personal Landfill Beyond the Stars.
- Attack of the 50-Foot Whatever: The Grow-Big Gumballs used by Sergeant Stinkbug causes anybody who eats them to grow bigger, eventually reaching gigantic proportions.
- Barefoot Cartoon Animals: Many of the mice aren't seen with any footwear.
- Bathroom Break-Out: Ricky does this to escape Mr. Mosquito to help Mighty Robot fight back (since Ricky's capture is the only thing preventing his Mighty Robot from fighting back).
- Be Careful What You Wish For: In Uranium Unicorns from Uranus, Ricky, easily annoyed by his robot's gigantic size given that he's a little mouse, makes a wish at night that the Robot should find another friend his own size so he won't have to hang out with him all the time. However, it turns out his wish has inspired a plan by the villains, who sent a giant Ladybot to fight with the Robot. Thus, Ricky changes his mind about his wish and ventures out to get his Robot back from the Ladybot.
- Bowdlerise: Voodoo Vultures from Venus was later rereleased as Video Vultures from Venus.
- A Boy and His X: A mouse boy and his mighty robot, who acts as his best friend and helps save the day.
- Bratty Half-Pint: Lucy, again.
- Berserker Tears: Lucy's reaction to being told by Ricky that if they don't destroy the evil robot in book 7 that there will be no more sweets in the world. Lucy does NOT take that well.
- Big "NO!": In Mecha Monkeys from Mars, Ricky shouts this after finding out his robot was kidnapped.
- Blazing Inferno Hellfire Sauce: Ricky laces some cookies with chili peppers and feigns being Brainwashed in order to defeat the Voodoo Vultures from Venus.
- Bully Hunter: Ricky becomes one in the first book after saving the robot from Dr. McNasty.
- Character Catchphrase:
- "It's about to get much worse" for Ricky, which he says when each main villain is defeated and complaining that their day can't get any worse, before they're then sent to prison.
- Also, each book ends with Ricky stating "that's what friends are for!"
- Continuity Cavalcade: Every book in the series ends with the villain getting thrown in jail next to the villains from the previous books. Uncle Unicorn noted it was getting crowded once he was tossed in there.
- In Stupid Stinkbugs from Saturn, one page shows inhabitants of previously visited planets dumping their trash on Saturn.
- Continuity Reboot: Went through one in 2014 after a 7-year hiatus.
- Cool and Unusual Punishment: In the first book, the Robot's evil creator, Dr. McNasty, tries to punish him by zapping him after he refuses to destroy Squeakyville. But then the Robot was saved by Ricky...
- Edible Theme Naming: Ricky's last name is a type of cheese. So are all the other mice in Ricky's town.
- The three Jurassic Jackrabbits, post-Heel–Face Turn, are named Cupcake (the Bunnysaurus Rex), Fudgie (the Trihareatops)note , and Waffles (the Rabbidactyl).
- Empathic Weapon: The Robot himself.
- Everytown, America: Squeakyville.
- Expy: Before the reboot, the Robot looked almost identical to The Iron Giant, except with mouse ears.
- Four-Fingered Hands
- Fossil Revival: General Jackrabbit uses his DNA with fossil skulls to create the Jurassic Jackrabbits. Sounds a lot like Jurassic Park.
- Funny Animal: The entire cast save the Robot.
- Gentle Giant: The Robot.
- George Lucas Altered Version: The first seven books were rereleased in May, July, and August 2014, with new full-color artwork by Dan Santat, who also did the artwork for the last two books.
- Hair-Raising Hare: General Jackrabbit, the villain of the fifth book. The Jurassic Jackrabbits also count before Ricky turned them good.
- Heel–Face Turn:
- The Jurassic Jackrabbits at the end of the fifth book, who become Lucy's pets and help her, her cousin, and the Robot in their adventures.
- Nigel and Clancy, President Penguin's chief guards, who intervene to save Lucy after their president subdues her and her pets and become their home dwarf planet's presidents afterward.
- Humble Kid Hero: Ricky.
- Humongous Mecha: The Robot, again. Note that this is only in relation to a mouse, in human size, he's only 2.5 feet.
- On the villains's side, there's the Major Monkey's Orangu-Tron in Mecha-Monkeys from Mars and Uncle Unicorn's Ladybot in Uranium Unicorns from Uranus.
- Hypno Ray: There's one built by the villains in Voodoo Vultures from Venus to hypnotize everyone in Squeakyville to give them all of the town's food supply. Then the villains from Uranium Unicorns from Uranus build one to make the Robot fall in love.
- I Just Want to Have Friends: Ricky in the first book.
- Ironic Echo: When Ricky meets up with his uncle and aunt, they both subject him to a tight handshake and sloppy kiss, saying "nobody wants a wimpy handshake" and "everyone loves kisses" respectively. The Robot then decides he wants to try too and gives them a taste of their medicine, while Ricky giggles and repeats their words.
- Landfill Beyond the Stars: In this series, the planet Saturn has become a massive dumping ground due to all the stinkbugs making it so. If you've read the story, you'll see exactly what we mean. Uranus is also one, with Uncle Unicorn having turned the planet into a radioactive waste dump.
- Lifesaving Misfortune: Ricky being grounded from watching television is the reason why the Venusian vultures were unable to brainwash him during their initial invasion.
- Mad Scientist: Every single villain.
- Mass Hypnosis: In Voodoo Vultures from Venus, the eponymous vultures hypnotize the citizens of Squeakyville into giving them all of their food after they all watched TV last night. Since Ricky was grounded from watching during that time, he's the only mouse unaffected.
- Mind-Control Eyes: The citizens of Squeakyville in Voodoo Vultures from Venus, and the Robot in Uranium Unicorns from Uranus. They all have the spiral-eyed variation.
- Mosquito Miscreants: Mr. Mosquito summons up a whole horde of these to invade Earth in a bid to escape from Mercury's horrible climate.
- Nice Mice: Ricky and most of the other Squeakyville citizens.
- Once per Episode:
- The Robot fighting the villains and throwing the chief one to jail.
- Then there's "Flip-O-Rama", like in Captain Underpants.
- Pluto Is Expendable: Scientists in Squeakyville no longer considering Pluto a "real" planet is President Penguin's motivation for attacking Earth.
- President Evil: President Penguin, who invades the Earth because it stopped classifying Pluto as a planet.
- Punny Name: Ricky's full name is a play on both the word "ricotta"note and the name of actor Desi Arnaz's character, Ricky Ricardo, from the show I Love Lucy. His Annoying Younger Cousin Lucy is also a reference to the show.
- Put on a Prison Bus/Falling into Jail: Every book ends with the Villain of the Week getting locked up in the same prison building, which gets increasingly full as the series goes on — and just so happens to have nine windows for all nine villains.
- Robot Buddy: One that's also a Humongous Mecha.
- Rodents of Unusual Size: The Mighty Robot's head looks vaguely like a mouse.
- Shout-Out:
- One book features "Hate Potion #9", a reference to the song "Love Potion No. 9".
- The aforementioned Punny Names of Ricky and Lucy are a reference to I Love Lucy, as are the names of Lucy's parents Fred and Ethel.
- One chapter is titled "Lucy in the Sky with Rubies".
- Show Within a Show: "Rocket Rodent" in Voodoo Vultures from Venus. It was Ricky's favorite show. The titular character is similar to Sparkster.
- Shrinking Violet: Ricky himself.
- Solar System Neighbors: Nearly the entire rogues gallery (with the exception of Dr. McNasty from the first book) are aliens from each of the Solar System's planets, and each of them invade Earth because of some aspect of their homeworlds that they do not like and want a better home.
- Strolling on Jupiter: The gas and ice giants are just as inhabited as the rest of the solar system.
- Tagalong Kid: Lucy.
- Take Over the World: It seems that this is the intent of every villain in the series. For Dr. McNasty, he simply wants to take the city over. For the other villains, they just aren't content with living on their home world for one reason or another. Admit it. None of them have ever played Master of Orion, so none of them know that in the game, there are technologies that can improve a planet's climate.
- Theme Naming: Lucy is named after Lucille Ball, who had a TV show called I Love Lucy, where she was married to a musician named "Ricky Ricardo". Also, Lucy's mother and father, Aunt Ethel and Uncle Freddy, were named after Fred and Ethyl Mertz, two other characters from the same show.
- Tickle Torture: Done by Ricky to Victor von Vulture in order to escape him in Voodoo Vultures from Venus.
- Tied-Together-Shoelace Trip: How the Ladybot is ultimately defeated in Uranium Unicorns from Uranus, courtesy of the Jurassic Jackrabbits.
- Tin-Can Robot: Well, the Robot.
- Try and Follow: In Uranium Unicorns from Uranus, Ricky does it to Lucy by telling her that everything she loves would be destroyed. She bursts into tears.
- Turned Against Their Masters: The Robot in the first book, towards Dr. McNasty.
- Unicorn: Uncle Unicorn and his Uranium Unicorn flunkies.
- Unnamed Parent: Ricky's parents are only known to the audience as "Ricky's mom" and "Ricky's dad".
- Versus Title: Every single book ever. Except for the first one, at least.
- Vile Vulture: Ricky Ricottas Mighty Robot vs. the Voodoo Vultures from Venus has the titular heroes fight Victor von Vulture and his army of alien vultures. The vultures perform a Mass Hypnosis on Squeakyville to force the residents to give them all their food.
- The Von Trope Family: Victor von Vulture is the Big Bad of Voodoo Vultures from Venus.
- World of Funny Animals: Solar system, actually.
- You Dirty Rat!: Dr. McNasty in the first book.
